Along with the advancement of the semiconductor technology, light emitting diodes now have the advantages of high brightness output, low power consumption, compactness, low driving voltage, mercury free. Therefore, the LED has been extensively applied in the field of displays and illumination.
A light emitting diode structure includes a light emitting diode chip and a peripheral wiring, wherein the light emitting diode chip includes a growth substrate and a semiconductor element layer. In general, the light emitting efficiency and the light extraction efficiency of a light emitting diode chip are related.
Currently, the light emitting efficiency is enhanced by improving the light extracting efficiency of the semiconductor element layer according to the existing techniques. For example, U.S. Pat. No. 7,053,420 discloses forming concaves and convexes on a growth substrate to increase the probability of light scattering and U.S. Pat. No. 6,091,085 discloses the increase the probability of light scattering via the formation of protrusions and depressions on the growth substrate. Apparently, to elevate the light efficiency is the attention focus and the research subject for researchers and the industry.